Note: Descriptions are shown in the official language in which they were submitted.
10433Z4
Background of the Invention
This invention relates to the mechanic arts, and partic-
ularly to the field of building demolition. It often happens
that the site of an urban renewal or other building project is
already occupied by structures which are not suited for the new
use, or are in ill repair, and hence must be removed. Such struc-
tures are frequently of frame construction and contain sheathing,
roofing, flooring, and similar boards which would have value for
reuse. Usually, however, no attempt is made to salvage this
material, and the whole structure is torn apart by a wrecking
crane and hauled away as trash to be disposed of. Sometimes this
is due to the pressure of time within which the new work must be
accomplished, but very often it is simply because the reclamation
of such used lumber is not economically feasible. The cost
of the labor needed to disassemble a structure in a way which
preserves usable materials is one factor, and another factor is
the relatively low yield of usable material due, for example, to
splitting of boards incidental to the wrecking process. The
usual tools employed in demolition are hammers and wrecking bars:
occasionally nail pullers are used, but pulling nails individu-
ally is a tedious process which is slow and hence expensive in
labor costs. The concentrated impact of hammer blows mars the
boards, and often causes breakage, while wrecking bars are almost
ideally designed to split boards lengthwise in the act of remov-
ing them.
I have invented a tool for use in demolishing frame
buildings, which is inexpensive, efficient, and easy to use, and
which acts on substantially the entire width of the board being
removed, rather than along one edge only, to continuously and
smoothly separate the board from the timber to which it is nailed.
My tool is usable in any position, to remove sheathing, roofing,
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or flooring boards, wherever access can be had to the rear surface of the
boards and the timbers to which they are nailed. My tool involves no impact
forces and no cross grain leverage forces, and hence its use results in a
high proportion of undamaged boards fît for salvage.
Summary of the Inventîon
My demolition tool comprises a demolition tool for separating
boards from tîmbers to which they are nailed comprising, in combination:
an elongated frame having a longitudinal axis and a guideway extending
along said axis between first and second ends of the frame; a member mounted
for linear movement in said guideway along said axis, and having an outer
end extending beyond said first end of said frame; means for removably
clamping said frame against a timber so that said axis is perpendicular to a
board to be removed, and said outer end of said member extends toward the
boards; and drive means operable to cause said linear movement of said mem-
ber whereby the latter contacts the board and forces it away from the timber.
Brief Description of the Drawings
In the accompanying drawings which illustrate exemplary embodiments
of the present invention:
Figure 1 is a plan view showing a demolition tool in use;
Figure 2 is a side elevation;
Figure 3 is a fragmentary view taken along the line 3-3 of Figure
l;
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FIGURE 4 is a sectional view taken along the line 4-4
of FIGURE 2;
EIGURE 5 is a sectional view taken along the line 5-5
of FIGURE 2;
FIGURE 6 is a sectional view taken along the line 6-6
of FIGURE 2; and
I FIGURE 7 is a fragmentary view of the tool showing a
modification.
Description of the Preferred Embodiment
As shown in the drawings, my invention comprises an
elongated frame 20 having a longitudinal axis 21 and a longitu-
dinal guideway 22 extending between a first end 23 and a second
end 24 of the frame. A member 25 is linearly movable along axis
21, and extends beyond the end 23 of the frame 20 at 26. Member 25
is fastened as by a threaded connection 27 to the body of a nut
30 which slides in guideway 22 without rotating about axis 21.
Cooperating with nut 30 is a screw 31. While elements 30 and 31
are shown as cooperating with a plurality of steel balls 32 and
recirculating tube 33 to comprise a low friction connection of
a well known type, a simple nut and screw with standard Acme or
square threads may be used if desired. Screw 31 has an enlarged
collar 34 beyond whicil it extends as a shaft 35 passing through
a thrust bearing 36, end 24 of frame 20, and a thrust washer 37.
An outer hub 40 is secured to shaft 35 as at 41, and is cross
bored to receive a crank 42 having a rotatable knob 43, and se-
cured in hub 40 as at 44.
Member 25 is hollow and the portion of screw 31 which
extends beyond nut 30 is contained within the member and carries
at its outer end 45 a disc 46 which is a loose fit in the hollow
47 of the member. Frame 20 has a face 50 which is parallel with
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axis 21. A plurality of teeth 51 extend away from face 50 and
are secured to end 23 of frame 20 by suitable fasteners 52.
A pressure foot 53 is removably retained in the end
26 of member 25 beyond end 23 by means such as a ball detent 58,
and extends perpendicular to axis 21. It is desirable that the
length of this foot be different for different applications, and
FIGURE 2 shows a second, longer foot 54 as being removably se-
cured on foot 53 by means such as a ball detent 59.
An arm 60 is secured to frame 20 near end 24, and ex-
tends from the frame in the same direction as teeth 51. Arm 60
has a pair of substantially parallel faces 61 and 62 generally
orthogonal to axis 21, and a carrier 63 is movable along arm 60.
At one end, carrier 63 rigidly is connected to a pair of shoes
64 and 65 having first parallel surfaces 66 and 67 spaced by
substantially the distance between surfaces 61 and 62. A second
pair of surfaces 70 and 71 make dihedral angles with the surfaces
66 and 67, respectively. The vertices of these angles are sub-
stantially in a plane parallel to axis 21, but may be slightly
offset so that the vertex of shoe 64 is slightly further from,
and that of shoe 65 is slightly nearer to, frame 20. The distance
between parallel surfaces 70 and 71 is greater than that between
surfaces 66 and 67 so that if carrier 63 is rotated in a counter-
clockwise direction the fit of the shoes on arm 60 is perceptably
looser. A set screw 72 is provided in shoe 65 to hold the carrier
in any desired position along arm 60.
A jaw 73 is pivoted to carrier 63 at 74, and a handle
75 is pivoted to carrier 73 at 76. The end of handle 75 is con-
nected to jaw 73 by a link 77, pivoted to the handle at 80 and
to the jaw at 81. Members 73 - 81 comprise an overcenter mechan-
ism 82 for locking arm 73 in a desired position. Link 77 may be
configured as at 83 to provide a stop in the overcenter condition
of the assembly.
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In order to make the use of my tool more convenient
where boards are to be removed from wider timbers, I provide an
extension 84 for member 25, as is shown in FIGURE 7. This
extension is arranged to cooperate with ball detent 58, and has
a similar ball detent 85 for cooperating with pressure foot 53.
Operation
My tool is used, as shown in FIGURE 1, in the following
fashion. It is desired to remove from a timber 90, such as a
two-by-four, a board 91 which is held to the timber by nails 92.
Set screw 72 is loosened to allow movement of carrier 63 along
arm 60, and a foot 54 slightly shorter than the width of the board
to be removed is used. With member 25 retracted as far as pos-
sible into frame 20 by the use of crank 42, the tool is positioned
so that foot 54 is against board 91 near timber 90, and face 50
is toward the timber with teeth 51 touching it. With handle 75
in the broken line position of FIGURE 1, carrier 63 is moved along
arm 60 toward timber 90 until jaw 73 is close to or touching the
timber, and handle 75 is then moved to its solid line position.
Th~ causes faces 66 and 67 to engage faces 61 and 62 securely,
and draws teeth 51 into the timber. Set screw 72 may be tighten-
ed, and the tool is now secured to timber 90. Operation of crank
42 rotates screw 31 to drive nut 30, and with it member 25, toward
board 91. Powerful forces are put into action and the board is
displaced smoothly from the timber, the nails usually being drawn
as well. Sometimes in old work, the head of a badly rusted nail
may be pulled through the board, but the hole thus produced is a
relatively minor imperfection in used lumber.
Handle 75 is now reversed to allow the teeth to be ex-
tracted from the timber, the tool is repositioned, and the work
continues. It will be apparent that the operation just described
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is simple to perform, requires no great strength of the operator,
is free from the noise and dust which accompany impact operations,
and has no tendency to split the boards.
While I have shown a screw as the driving element for
member 25, it will be apparent that mechanical equivalents may
be used as preferred. I also contemplate that for major demoli-
tion projects, my member 25 may be arranged for pneumatic or hy-
draulic actuation, when this additional complication is felt
justified.
From the above it will be evident that I have invented
a demolition tool which is simple, easy to use, relatively inex-
pensive, quiet and clean, which may be used to remove boards of
various widths from timbers of various thicknesses, which causes
minimum damage to the lumber being reclaimed, and which may be
arranged for either manual or fluidic actuation.
Numerous characteristics and advantages of my invention
have been set forth in the foregoing description, together with
details of the structure and function of the invention, and the
novel features thereof are pointed out in the appended claims.
The disclosure, however, is illustrative only, and changes may
be made in detail, especially in matters of shape, size, and
arrangement of parts, within the principle of the invention,
to the full extent indicated by the broad general meaning of
the terms in which the appended claims are expressed.
